An intact keratin network is crucial for mechanical integrity and barrier function in keratinocyte cell sheets
An intact keratin network is crucial for mechanical integrity and barrier function in keratinocyte cell sheets
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DOI：
10.1007/s00018-019-03424-7
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发表时间：
2020-01-07
影响因子：
8
通讯作者：
Janshoff, Andreas
中科院分区：
文献类型：
--
作者：
Karsch, Susanne;Buechau, Fanny;Janshoff, Andreas
角蛋白细胞骨架的同型特异性组成对表皮的强粘附、力弹性和屏障功能至关重要。然而，角蛋白调节这些功能的机制仍然不完全清楚。在本研究中，我们分析了角蛋白网络在小鼠角质形成细胞中机械完整性、力传递和屏障形成方面的作用和意义。在单细胞伤口闭合的时间过程中，野生型（WT）细胞以一种集体的方式缓慢地闭合闭合间隙，包括紧密连接的相邻细胞。相反，在角蛋白缺乏的细胞中，邻近细胞的机械反应受到损害，导致最初的伤口面积增加，整体伤口愈合效率低下。此外，角蛋白网络的缺失导致细胞-细胞连接受损、碎片化，并引发整个细胞肌动球蛋白结构的深刻变化。与WT细胞相比，细胞连接处的电-基质阻抗传感揭示了敲除（Kty(-/-)）细胞的功能障碍。这些发现表明，Kty（-/-）细胞表现出一种以机械偶联丧失和无法形成功能屏障为特征的新表型。K5/K14的重新表达在很大程度上挽救了屏障缺陷，并重建了机械偶联，剩余的差异可能是由于在这种情况下角蛋白的丰度较低。我们的研究揭示了角蛋白网络在角化细胞层的机械稳态和屏障功能中的主要作用。
The isotype-specific composition of the keratin cytoskeleton is important for strong adhesion, force resilience, and barrier function of the epidermis. However, the mechanisms by which keratins regulate these functions are still incompletely understood. In this study, the role and significance of the keratin network for mechanical integrity, force transmission, and barrier formation were analyzed in murine keratinocytes. Following the time-course of single-cell wound closure, wild-type (WT) cells slowly closed the gap in a collective fashion involving tightly connected neighboring cells. In contrast, the mechanical response of neighboring cells was compromised in keratin-deficient cells, causing an increased wound area initially and an inefficient overall wound closure. Furthermore, the loss of the keratin network led to impaired, fragmented cell-cell junctions, and triggered a profound change in the overall cellular actomyosin architecture. Electric cell-substrate impedance sensing of cell junctions revealed a dysfunctional barrier in knockout (Kty(-/-)) cells compared to WT cells. These findings demonstrate that Kty(-/-)cells display a novel phenotype characterized by loss of mechanocoupling and failure to form a functional barrier. Re-expression of K5/K14 rescued the barrier defect to a significant extent and reestablished the mechanocoupling with remaining discrepancies likely due to the low abundance of keratins in that setting. Our study reveals the major role of the keratin network for mechanical homeostasis and barrier functionality in keratinocyte layers.